!-------------------------------------------------------------LICENSE--------------------------------------------------------------!
!                                                                                                                                  !
!The MAP code is written in Fortran language for magnetohydrodynamics (MHD) calculation with the adaptive mesh refinement (AMR)    !
!and Message Passing Interface (MPI) parallelization.                                                                              !
!                                                                                                                                  !
!Copyright (C) 2012                                                                                                                !
!Ronglin Jiang                                                                                                                     !
!rljiang@ssc.net.cn                                                                                                                !
!585 Guoshoujing Road. Pudong, Shanghai, P.R.C. 201203                                                                             !
!                                                                                                                                  !
!This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License         !
!as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.             !
!                                                                                                                                  !
!This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of    !
!MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.                        !
!                                                                                                                                  !
!You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software     !
!Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.                                                   !
!                                                                                                                                  !
!-------------------------------------------------------------LICENSE--------------------------------------------------------------!

!==================================================================================================================================|
subroutine bnd_fixe_2d (ro, mx, my, mz, bx, by, bz, en, gx, gy, po, x, y, nx, ny, ng, dir, sides)
!==================================================================================================================================|
!  sides = 'l' for lower boundary
!  sides = 'h' for higher boundary
!  sides = 'b' for both
!----------------------------------------------------------------------------------------------------------------------------------|

   implicit none

   character(1), intent(in) ::  dir, sides
   integer(4), intent(in) :: nx, ny, ng
   real(8), dimension(nx), intent(in) :: x
   real(8), dimension(ny), intent(in) :: y
   real(8), dimension(nx, ny), intent(inout) :: ro, mx, my, mz, bx, by, bz, en, gx, gy, po

   integer(4) :: i_start, j_start, i_end, j_end

!----------------------------------------------------------------------------------------------------------------------------------|
!  initialization
!----------------------------------------------------------------------------------------------------------------------------------|
   if (dir .eq. 'x' .and. sides .eq. 'l') then
      i_start = 1
      i_end = ng
      j_start = 1
      j_end = ny
   elseif (dir .eq. 'x' .and. sides .eq. 'h') then
      i_start = nx - ng + 1
      i_end = nx
      j_start = 1
      j_end = ny
   elseif (dir .eq. 'y' .and. sides .eq. 'l') then
      i_start = 1
      i_end = nx
      j_start = 1
      j_end = ng
   elseif (dir .eq. 'y' .and. sides .eq. 'h') then
      i_start = 1
      i_end = nx
      j_start = ny - ng + 1
      j_end = ny
   endif

   call model_variables (ro(i_start : i_end, j_start : j_end), mx(i_start : i_end, j_start : j_end),                               &
                         my(i_start : i_end, j_start : j_end), mz(i_start : i_end, j_start : j_end),                               &
                         bx(i_start : i_end, j_start : j_end), by(i_start : i_end, j_start : j_end),                               &
                         bz(i_start : i_end, j_start : j_end), en(i_start : i_end, j_start : j_end),                               &
                         gx(i_start : i_end, j_start : j_end), gy(i_start : i_end, j_start : j_end),                               &
                         po(i_start : i_end, j_start : j_end), x(i_start : i_end), y(j_start : j_end),                             &
                         i_end - i_start + 1, j_end - j_start + 1)

!----------------------------------------------------------------------------------------------------------------------------------|
   return
end subroutine bnd_fixe_2d
